The word "城镇" is formed by combining two characters, each representing a type of settled place, to create a single, broader concept. The first character, "城" (chéng), originally depicts a walled city or urban center, evoking a sense of fortification and administrative importance. The second, "镇" (zhèn), traditionally refers to a market town or a garrison settlement, smaller than a city but a key nodal point. By joining them, the compound "城镇" doesn't simply list two things; it conceptually merges their defining characteristics to encompass the entire spectrum of human settlements, from larger, more central cities down to smaller, organized towns, effectively meaning "cities and towns" as a unified idea of urbanized places.